Abstract: In a communication system (SYS) circuit switched data frames (DF) are disassembled into ATM cells (CL), routed through an ATM routing network (RN) and cell data is reassembled into data frames (DF) by a frame assembly device (FAD). Second type cells including a pointer value (PTR) are normally included in the cell stream (CS) received from the ATM routing network (RN). This pointer value (PTR) indicates the delimitation position, i.e. the number of data units belonging to a current frame (DF) and to a next frame (DF?). In order to avoid a loss of data units of a complete frame when such a second type cell (STC) is lost during the transmission, the invention estimates the sequence number of the missing second type cell as well as the pointer value (PTR?). The pre-estimation of the pointer value (PTR?) can be done by continuously updating a respective counter assigned to a respective sequence number (SN) of a cell block (CB).

Abstract: In a communication system (SYS) circuit switched data frames (DF) are disassembled into ATM cells (CL), routed through an ATM routing network (RN) and cell data is reassembled into data frames (DF) by a frame assembly device (FAD). Second type cells including a pointer value (PTR) are normally included in the cell stream (CS) received from the ATM routing network (RN). This pointer value (PTR) indicates the delimitation position, i.e. the number of data units belonging to a current frame (DF) and to a next frame (DF′). In order to avoid a loss of data units of a complete frame when such a second type cell (STC) is lost during the transmission, the invention estimates the sequence number of the missing second type cell as well as the pointer value (PTR′). The pre-estimation of the pointer value (PTR′) can be done by continuously updating a respective counter assigned to a respective sequence number (SN) of a cell block (CB).